Apparatus for cementing wells



J. w. KLoMP APPARATUS FOR CEMENTING WELLS June 27, 1939.

Filed Feb. 25, 1937 FIC-'1.2

INVENTOR: Johan MHem Kiomp 'BY 111s ATTORNEY-@W im Patented June 27, `1939 I APPARATUS FOR @EMENTING WELLS Johan Willem Klomp, Boldesti, Rumania, assignor to Shell Development Company,

San Francisco, Calif., a corporation'of Delaware Application February 23, 1937, In Rumania March 4 Claims.v

This application pertains to the menting wells and relates spported by a string of casing 5 extendingr to the surface.

hen cementing a liner,

tion of the casing whichextencls to the surface cement charge to 13 liner, thereby cementing the liner.

This method of operation presents, however, some serious disadvantages. First, the cement mixture cannot be prevented from mixing with mixing of the two liquids within 35 thereby prevented.

i Referring to Fig. 1, I indicates a borehole into Serial No. 127,058 3, i936 toY connect a collar t, which in turn supports, by means of screw-threads ll, the liner it, which is to be y cemented. t

pple 'l is screwed into the lower part of apter the liner lll is attached to the mandrel il, for example, by means of serrations l5 carried by the mandrel d. The periphery of the packer with recesses lil to The lower portion of the liner or of string is provided at a desired depth with a constriction or other means for limiting the downward stroke of piston it, such,

the liner.I

it, seating up- The plug lll may be constructed in any desired form, for example as an adapter to which another liner, such as the perforated liner shown at il, may be attached.

In operation, the following procedure may be followed:

A liner string of suitable length is made up at the surface and lowered into the borehole at the end of a drill string to the place where it is to be cemented.

such as rmudlush, to force the cement ont of the drill pipe and liner. At the moment when the the drill pipe. 'I'hls sealing body is of a diameter such as to pass through the` drill pipe, and has a specific gravity greater than that of the mudush, but less than that of 55 the cementing mixture, being therefore adapted to keep at the interface of the two fluids. The sealing body may be a suitably weighted hollow metallic bali or a ball made of a composition material of suitable specinc gravity. If a drill pipe .having externally upset couplings of the flush-joint type is used, the sealing body may be given the shape of a small piston provided with rubber packing as shown in Fig. 2.

The sealing body, being of a diameterv only slightly smaller than that of the drill pipe, prevents any appreciable mixing of the cement with the pressure fluid within the drill pipe, in which it travels downwards at the interface of the two fluids.

When the cementing mixture has been forced out of the drill pipe into the liner by the action of the pressure fluid, the sealing body comes to rest against the seat IIJ in mandrel 9. The rise in pressure due to the closing of the axial passage through the mandrel 9 is sufficient to shear off the rivets 8 attaching said mandrel and the piston I2 to the nipple v1, whereupon the piston I2 moves downwardly under the action of the pressure fluid and forces the cement mixture out of the liner. In some cases, the rivets B may be dispensed with, the piston I2 being retained in its uppermost position by friction against the walls of liner III during the time when the cementing fluid is being pumped dow-n.

When the piston I2 reaches the end of its desired stroke its further motion is stopped by the plug II, and the resulting rise of pressure indi- Cates to the operator that the desired amount of the cement charge has been forced out of the liner. The pumping of the pressure fluid is thereupon stopped, the non-return valve I8 preventing an upward return ofthe cement mixture into the liner which is sometimes caused by formation back-pressure. The cemented liner maybe readily disconnected from the drill pipe by suitably rotating the latter, the adapter 4 being, as stated above, attached to the collar 6 by means of lefthand screw-threads.

I claim as my invention:

l. In an apparatus for cementing wells, a pipe string, a liner attached to the end thereof, a piston yieldably held within the upper portion of the liner, a fluid `passage through the piston means for placing a cement charge below the piston through said passage, means fori closing said passage, and means for applying to the upper face of said piston a suicient fluid pressure to move the piston downward when the passage placed below its therethrough is closed, said piston being effective in forcing out of the liner the cement charge lower face.

2. In an apparatus for cementing wells, a pipe string, a liner attached to the end thereof, a piston fitting within the upper end of the liner, frangible means for retaining said piston in its uppermost position, a fluid passage through the piston, means for placing a cement charge below the piston through said passage, means for closing said passage, a plug within the lower portion of the liner, a fluid passage through said plug, and means for applying to the upper face of the piston a sufficient fluid pressure for breaking said `frangible means and moving the piston downwards when the fluid passage therethrough is closed, said piston being effective' in forcing out of the'liner the cement charge placed below its lower face.

3. In an apparatus for cementing wells, a pipe string, pumping means to force a cement charge and a pressure fluid down said string, a liner attached to the end of said string, a piston yieldably held within the upper portion of the liner, a fluid passage through the piston for placing a cement charge below the piston. floating means maintained by gravity at the interface between the cement and the pressure fluid for closing said passage, said pumping means being adapted to apply to the upper face of said piston a sufllcient fluid pressure to move the piston downwards when the passage therethrough is closed, said piston being effective in liner the cement charge placed below said piston.

4. In an apparatus for cementing wells, a pipe string, pumping means to force a cement charge and a pressure fluid down said string, a liner at tached to the end of said string, a piston yieldably held within a fluid passage through the piston for placing a cement charge below the piston, floating means maintained by .gravity at the interface between the cement and the pressure fluid for closing said passage, said pumping means being adapted to apply to the upper face of said piston a sufficient fluid pressure to move the piston downwards when the passage therethrough is closed, said piston being effective in forcing out of the liner the cement charge placed below said piston` and means carried by the liner to arrest the downward motion of the piston, thereby causing a rise in the pressure of the fluid within the string.

JOHAN WILLEM KLOMP.

the upper portion of the liner, 

